Traditionally, penetration of an invasive medical device such as a needle and catheter tubing through skin tissue to reach the vein during catheter insertion is invisible to clinicians. For this reason, clinicians must rely on their first-hand experience with needle insertion in combination with tactile sense to successfully identify the location of the vein. This may be a difficult task when attempting to access a small vein in a deep location under the skin, thereby increasing the risk of excess pain and/or injury to the patient. There are similar problems with insertion of other invasive medical devices such as guidewires, catheters, introducer needles, stylets, scalpel and guidewire with respect to the inability to precisely visualize the location of the invasive medical device.
Emerging procedural guidance systems utilize a combination of ultrasound and magnetic technologies to provide visualization of subdermal anatomy and device position in the in-plane and out-of-plane orientations. This combination of ultrasound and magnetic methods also allows for the projection or anticipation of the insertion device position relative to the patient's anatomy, and thereby improves the likelihood of successfully accessing the vascular and completing the invasive procedure. The ultra-sound and magnetic procedural guidance system technology requires that the invasive device have a sufficient magnetic field source that is maintained throughout the procedure.
In some current needle guidance systems, a magnetic field is generated just prior to insertion of the needle by magnetizing the needle by burying the metal cannula of the needle into a separate external needle magnetizer until the point of the needle hits a rubber stopping surface. FIG. 1 shows a perspective view of a currently available separate external needle magnetizer 11. As shown in FIG. 1, current practice uses an unprotected needle 13 that is placed within the separate external needle magnetizer 11 to a depth defined by the bottom of the magnetizer. The current devices for magnetizing a needle prior to insertion generally are not sterile and are not disposable.
In systems of the type shown in FIG. 1, damage to the needle can occur that is not apparent to the user that can negatively affect the insertion process. Also, the step of the user actively magnetizing the metal cannula has some limitations and inherent risks as this approach does not guarantee consistent magnetization since variability in clinician procedures such as depth of insertion, speed of process, and centering of the needle in the magnetizer will result in different degrees of magnetization. Considering the potential inconsistency of a user fully inserting the needle to the bottom of the magnetizer 11, the significant risk of damaging the needle tip, and the increased potential for contamination during this step, it would be advantageous to have a system that passively and consistently magnetizes the needle without introducing the aforementioned additional risks, such as needle tip damage and increased potential for contamination.
Thus, there is a need for a system that passively and consistently magnetizes invasive medical devices thereby reducing or eliminating risks, such as needle tip damage and needle contamination while providing magnetic shielding to minimizing any effects to the clinical environment from magnetic fields generated within the cover.